1. Field of the Invention
The present invention relates to a method and an apparatus for manufacturing a workpiece by applying desired manufacturing processes with respect to a workpiece which requires a plurality of manufacturing steps.
2. Description of the Background Art
A long workpiece with a complex cross sectional shape is usually used for a pressing of automobile and an architectural window sashes. Such a long workpiece requires its end portions to be manufactured by a manufacturing process comprising multiple steps including such steps as cutting, chipping and piercing. In such a manufacturing process, desired shapes at end portions are obtained by applying the manufacturing steps for each portion separately, using a plurality of metal press dies corresponding to each of the manufacturing steps.
Conventionally, in a manufacturing apparatus for applying such a manufacturing process a plurality of metal press dies are linearly arranged on a single press apparatus, and workpieces are carried in and out with respect to each metal press die and transferred by a worker, as disclosed in U.S. patent application Ser. No. 4,676,090 by Nishmura et al.
Now, in such a conventional manufacturing apparatus, the workpiece has to be transferred to positions corresponding to a plurality of metal press dies in order, so that the work is cumbersome, time consuming, and less productive. Because of this, a use of a robot operating under a numerical control to transfer the workpiece with respect to the press apparatus may be considered.
However, the press apparatus has a large size because the plurality of metal press dies are linearly arranged, which is particularly so in cases such as that for an automobile window sashes in which manufacturing steps for a long workpiece exceeds ten steps, so that a required operational region of the robot becomes quite enlarged, and as result an automatization of the manufacturing becomes difficult.